[crac] RFR: Merge jdk:jdk-25+18

[Timofei Pushkin]

On Mon, 16 Jun 2025 07:31:21 GMT, Dmitry Cherepanov <dcherepanov at openjdk.org> wrote:

> This MR includes merges for tags between jdk-25+15 and jdk-25+18.
> 
> Attaching output of --diff-merges=remerge
> 
> <details>
> 
> <summary>jdk-25+15</summary>
> 
> 
> commit b0b66cb5999e89dd44456682c6bc932fa559e242
> Merge: eea5480cdda 74df384a987
> Author: Dmitry Cherepanov <dcherepanov at azul.com>
> Date:   Mon Jun 9 18:31:26 2025 +0400
> 
>     Merge with jdk-25+15
> 
> diff --git a/src/hotspot/os/posix/attachListener_posix.cpp b/src/hotspot/os/posix/attachListener_posix.cpp
> remerge CONFLICT (content): Merge conflict in src/hotspot/os/posix/attachListener_posix.cpp
> index ca3666be119..4fcb7a24e08 100644
> --- a/src/hotspot/os/posix/attachListener_posix.cpp
> +++ b/src/hotspot/os/posix/attachListener_posix.cpp
> @@ -60,105 +60,6 @@
>  //    obtain the credentials of client. We check that the effective uid
>  //    of the client matches this process.
>  
> -<<<<<<< eea5480cdda (8358956: [CRaC] Fix NULL usage in hotspot)
> -=======
> -// forward reference
> -class PosixAttachOperation;
> -
> -class PosixAttachListener: AllStatic {
> - private:
> -  // the path to which we bind the UNIX domain socket
> -  static char _path[UNIX_PATH_MAX];
> -  static bool _has_path;
> -
> -  // the file descriptor for the listening socket
> -  static volatile int _listener;
> -
> -  static bool _atexit_registered;
> -
> - public:
> -  static void set_path(char* path) {
> -    if (path == nullptr) {
> -      _path[0] = '\0';
> -      _has_path = false;
> -    } else {
> -      strncpy(_path, path, UNIX_PATH_MAX);
> -      _path[UNIX_PATH_MAX-1] = '\0';
> -      _has_path = true;
> -    }
> -  }
> -
> -  static void set_listener(int s)               { _listener = s; }
> -
> -  // initialize the listener, returns 0 if okay
> -  static int init();
> -
> -  static char* path()                   { return _path; }
> -  static bool has_path()                { return _has_path; }
> -  static int listener()                 { return _listener; }
> -
> -  static PosixAttachOperation* dequeue();
> -};
> -
> -class SocketChannel : public AttachOperation::RequestReader, public AttachOperation::ReplyWriter {
> -private:
> -  int _socket;
> -public:
> -  SocketChannel(int socket) : _socket(socket) {}
> -  ~SocketChannel() {
> -    close();
> -  }
> -
> -  bool opened() const {
> -    return _socket != -1;
> -  }
> -
> -  void close() {
> -    if (opened()) {
> -      ::shutdown(_socket, SHUT_RDWR);
> -      ::close(_socket);
> -      _socket = -1;
> -    }
> -  }
> -
> -  // RequestReader
> -  int read(void* buffer, int size) override {
> -    ssize_t n;
> -    RESTARTABLE(::read(_socket, buffer, (size_t)size), n);
> -    return checked_cast<int>(n);
> -  }
> -
> -  //...

I'm having doubts on JDK-8319055 resolution. I don't see where the connection between `effectively_complete_raw` and `complete` is now? How is it ensured they don't do the same (write the result) twice?

Before this I see that VM thread would call `effectively_complete_raw` before checkpoint which would write the reply and close the socket, then after restore attach listener thread would call `complete` which would **just cleanup the memory**. Now `effectively_complete_raw` will be called as before but after restore `complete` will be called and **try to write something again**?

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PR Comment: https://git.openjdk.org/crac/pull/238#issuecomment-2995716304